spi/imx: prevent NULL pointer dereference in spi_imx_probe()

When no platform_data is present and either 'spi-num-chipselects' is
not defined in the DT or 'cs-gpios' has less entries than
'spi-num-chipselects' specifies, the NULL platform_data pointer is
being dereferenced.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 373f4fff9358..570f22053be8 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -766,8 +766,12 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
         }
 
         ret = of_property_read_u32(np, "fsl,spi-num-chipselects", &num_cs);
-        if (ret < 0)
-                num_cs = mxc_platform_info->num_chipselect;
+        if (ret < 0) {
+                if (mxc_platform_info)
+                        num_cs = mxc_platform_info->num_chipselect;
+                else
+                        return ret;
+        }
 
         master = spi_alloc_master(&pdev->dev,
                         sizeof(struct spi_imx_data) + sizeof(int) * num_cs);
@@ -784,7 +788,7 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
 
         for (i = 0; i < master->num_chipselect; i++) {
                 int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
-                if (cs_gpio < 0)
+                if (cs_gpio < 0 && mxc_platform_info)
                         cs_gpio = mxc_platform_info->chipselect[i];
 
                 spi_imx->chipselect[i] = cs_gpio;